More Musings of an Energy Nerd

If you’re shopping for a garage door, the door’s energy performance may not matter — especially if you don’t heat your garage. However, there are a few reasons why you might be looking for a well-insulated, draft-free garage door:

A good overhead door on an attached garage can keep the garage — and therefore the house — a little warmer than a leaky door.

Since cars can be hard to start in sub-zero weather, homeowners in very cold climates — even those with unheated garages — may want a garage door that limits heat loss.

If the garage is used for vehicle maintenance or woodworking projects, it may occasionally be heated.

So, how do you tell a high-performance garage door from a lemon?

“We sell high R-value doors!”

Many garage-door manufacturers advertise the R-values of their doors:

advertises doors with R-17.09 polyurethane insulation.

advertises that some of its doors are R-17.2.

advertises that “a 17.5 R-value makes the 490 Series among the most thermally efficient doors you can buy.”

To determine the thermal performance of a garage door, you need to know two things:

The door’s leakiness, and

The R-value or U-factor of the entire door assembly.

The R-values that are trumpeted by garage-door manufacturers are measured at the center of one of the door panels. No manufacturer, as far as I can determine, reports the R-value of the entire door assembly (including the panel edges, the seams between panels, and the perimeter of the door) in their promotional materials. Moreover, manufacturers’ reported R-values tell us nothing about air leakage.

Most garage-door manufacturers are reluctant to share actual laboratory reports showing the results of R-value testing. When I asked Mike Willstead, a technical representative for Raynor, if I could see a copy of Raynor’s test results, he suggested I send him an e-mail. He later e-mailed his response: “I apologize if I misled you. I was informed that this is proprietary information that will not be disclosed.”

The window industry does a much better job

More than a decade ago, responsible window manufacturers realized that the reputation of their industry was being damaged by misleading R-value and U-factor claims. (U-factor is the inverse of R-value; in other words, U=1/R and R=1/U). To address these problems, industry leaders developed a method for testing and reporting whole-window U-factors. The U-factor reported on an NFRC label accurately describes the U-factor of the entire window, including the sash frame and the window frame — not just the center-of-glass U-factor.

When it comes to accurate reporting of U-factors or R-values, however, the garage door industry is years behind the window industry.

There’s nothing to prevent garage-door manufacturers from using the NFRC testing and labeling protocol — a protocol that yields a more honest and useful result than the center-of-panel numbers trumpeted by garage-door marketers. Alternatively, garage-door manufacturers could use the voluntary consensus standard (ANSI/DASMA 105) for reporting whole-door U-factors adopted by the Door and Access System Manufacturers Association (DASMA). A technical data sheet (DASMA TDS #163) describes this testing protocol, dubbed the “tested installed door” protocol by DASMA.

“For marketing purposes, the garage door people get a measurement on the center of panel,” said David Yarbrough, a research engineer and insulation expert at R&D Services in Cookeville, Tennessee. “The overall R-value of the entire door might be quite a bit less — in extreme cases, it may be half — of the R-value of the center of the panel. Not everyone approves of this kind of marketing. It’s been a hot debate in recent years.”

In fact, the percentage turns out to be much less than half.

Actual R-values are one-third the advertised values

Although it’s hard to obtain actual test results that report the whole-door U-factors of “tested installed doors,” I managed to obtain one report on a garage door from Clopay, and another on a garage door from Overhead Door.

Clopay provided test results for their model 3720 five-panel garage door. According to Mischel Schonberg, Clopay’s public relations manager, the door is insulated with 2 inches of polyurethane foam. Schonberg wrote, “This model is the commercial version of our residential model 9200 and has the same construction.”

While Clopay advertises that the 9200 door is R-17.2 — presumably, a claim based on a center-of-panel measurement — the test report for the installed door shows R-6.14.

While Overhead Door advertises that their model 494/495 Thermacore door has an R-value of 17.5 — a claim that, like competitors’ claims, is presumably based on a center-of-panel measurement — the test report for the installed door shows a U-factor of 0.16, equivalent to R-6.25.

Based on the only two test reports that I was able to track down, it seems logical to conclude that the R-value of a garage door is about one-third of the R-value claimed in a manufacturer’s brochure.

All over the map

Mike Thoman, the director of thermal testing and simulation at Architectural Testing Incorporated, a Pennsylvania laboratory, has tested many garage doors.

“The assembly R-values are not going to be nearly as good as the R-value of the material would indicate,” Thoman told me recently. “When you compare the assembly R-value to the material R-value, the percentages are all over the map. The percentage is a function of how the joints in the panels are made, and whether any attempt was made to provide for thermal breaks at panel edges — a lot of different things. Some products have a lot of insulation in the panel but have everything else wrong. We’ve also seen doors that do everything right. There’s really a wide, wide range.”

Are the reported R-values even accurate?

There’s another potential problem with the R-values reported by garage-door manufacturers: even if one accepts the fact that the advertised R-values represent center-of-panel values rather than whole-door values, the numbers are still higher than most insulation experts believe are possible.

Several manufacturers report that their polyurethane-insulated door panels have R-values between R-8.6 and R-9.0 per inch — values that are highly unlikely if not technically impossible, even for the center of a door panel.

“The R-value of polyurethane decreases with age,” said Yarbrough. “When it is absolutely fresh you might get R-7.5 per inch, but a realistic aged R-value would be lower — perhaps about R-6.5 per inch would be on the high end. I’m not sure I can explain these reported test results. I have seen labs make mistakes before. I think it’s an error.”

One garage-door distributor who doubts the accuracy of manufacturer’s R-value claims is Bill Feder, the president of Door Services Incorporated of Portland, Maine. On his own initiative, Feder sent a garage-door panel (Overhead Door model 194) to Yarbrough’s lab, R&D Services. The ASTM C518 test conducted by Yarbrough came up with a value of only R-7.83 for the 1 3/8-inch-thick panel. Yet Overhead Door advertises that the door is R-12.76 — or R-9.28 per inch.

Feder’s R-value challenge

“If anyone calls me about a door, I tell them about my R-value challenge,” Feder told me. “I will give anyone a check for $250 if they can bring in a document that shows that a 1 3/8-inch-thick garage door has an R-value of 12. They can’t do it.”

Unfortunately, Feder’s admirable challenge has not yet shamed the garage-door industry into correcting the numerous exaggerations in their product specifications.

What about air leakage?

If the day ever comes when garage-door manufacturers follow the path blazed by their more honest brothers and sisters in the window industry — that is, if they ever decide to report whole-door U-factors or whole-door R-values — an important piece of the door-rating puzzle will still be missing. The reason: when it comes to the thermal performance of garage doors, air leakage matters much more than R-value.

“Garage doors are so leaky that they are difficult to test,” Thoman said. “Their leaks exceed the capabilities of the available testing apparatus.”

When he needed to buy a garage door for his own house, Thoman ignored advertised R-values. “I find it almost offensive that garage-door manufacturers even publish the R-value of the insulation material,” Thoman told me. “I hate it when I see that, because it’s not a representation of the door’s performance. Air leakage is a much more important issue than the R-value of the door.”

The bottom line

Although some garage-door manufacturers have measured the whole-door U-factor and air-leakage characteristics of their doors, most won’t release the data. Until they do, purchasers of garage doors have to select their doors based on anecdotes.

If any readers have identified a garage door that limits air leakage, please tell us the brand. When you post your garage door recommendations, provide your full name — so we can tell the garage-door salespeople from the architects, builders, and homeowners.

“I tell customers that the R-value of the door should be the last thing you should think about,” Bill Feder told me. “Instead, look at the seals and the hardware. On my own garage I just have a raised-panel cedar door.”

48 Comments

Please consider a follow up piece
Nice piece Martin! You have established the many problems of finding accurate whole door thermal performance information on garage doors. Now we know the problems but how do we sort the wheat from the shaft? Would you please consider writing a follow up blog post on which doors are "doing everything right" in the words of Mike Thoman? If you focused on exactly what "doing everything right" is in terms of door construction that could be very instructive. Thanks!

I hope I can do a follow-up
Kyle,
I'm depending on the community of GBA readers to contribute recommendations on good garage doors (and even installation tips that limit infiltration).

Sorting the wheat from the chaff is frustratingly difficult. Mike Thoman was unable to release specifics on the brand names of better doors because of confidentiality agreements signed with the manufacturers who submit their doors for testing.

Manufacturers are tight-lipped and reluctant to release lab reports.

This is what I know:
-- Designs that minimize air leakage are the best, so look for good gaskets between panels and heavy-duty weatherstripping at the bottom of the door.
-- Thin-gauge steel doesn't last as long as heavier gauge steel, so avoid doors with thin 32-ga. steel. Look instead for 24 ga. or 25 ga. steel -- or just choose a wood-panel door.

U-values of garage doors
Well informed article, and very timely for me. I serve on a task group that is writing new building efficiency standards for Canada, and we are currently considering mandating U-values and test procedures for overhead doors. Thanks for the insight.

Good luck, Rick
Rick,
I'm glad the article was useful. And good luck with your efforts to mandate U-factors and test procedures for overhead doors. I look forward to seeing what your task group recommends.

Anything on Thermacore 190 or 490 series
Very good article. I'm in the process of looking for two doors. Have you heard of anything on Overhead Door's Thermacore 190 or 490 series. The 490 series claims the R-value as 17.5, while the 190 series claims an R-value of 12.76. I can't seem to find out the steel gauge but I assume it is 24 or 25. Any info would help

Most Homeowners Are Too Overwhelmed
We install and repair doors all day, and, unfortunately, for a lot of people energy efficiency still isn't at the top of their list when it comes to the garage door. We try our best to educate, but often times the most homeowners are willing to go is repairing or adding rubber stop molding. I think what the industry needs is, like you mentioned, less anecdotes and more scientific evidence like the window manufacturers have. Some quantifiable facts about how installing the proper door is going to save them X dollars a year.

R-value depends on weather strip etc...
We are a manufacturer of carriage doors in Maine with weather all over the map. I have found that R-value is indeed misleading. We tell people exactly what you have stated here - that panel core and thickness do matter (we prefer polyiso instead of the cheap white foam board), but more important is the weather seal around the sides and the door bottom as well as integrity of the concrete surface the door sits on.

Also, look for a door section that has a good male/female interlocking frame - you'd be surprised by the weather that can sneak in between the panels. It's true that the entire "package" should be rated and results provided to the customer and yes, proper installation of both door and weather seal can make or break the entire system.

Garaga
I just saw your post jim. We sell Garaga weather seal with our custom carriage doors. It's one of the best on the market with a double rubber seal around the top and side jambs. - Scott from Maine Doors.

testing
Bill Feder is right. The testing is misleading and fairly expensive for a company to do because it's really not about the door - it's about the entire package. If it's installed improperly - you're wasting your money on a high R door.

Sealing the door is the ticket!
Great article! In fact, it inspired me to post info on my own garage door replacement, since a number of people asked me how I did mine. Info is here... and again, thanks for the article.
-Rod

Prey on the unknowing
Door manufactors have been doing this for years. When I get a call from a customer and the first thing they ask is R -value of our doors I know my work is cut out for me. I can show samples with the same insulation and thickness with wildly different claimed R values. If they are lying about this what else are they lying about??? The same applies to gauge of steel on panels. 25 gauge is not the same thickness among manufactors. This principles applies to track, hinges, rollers, springs, etc... Thermo breaks between panel and end stiles along with perimater and bottom seal is also very important.. Keep in mind this is the largest moving part on a home and there will be trade offs. Bottom line different types of insulation only have so much R per inch. Do the manufactors claims match this?

Energy Tax Credit
I recently bought new windows for my bedroom, and knowing what type and applying for the energy tax credit was real simple. The window industry just has their stuff together, whereas the garage door industry hasn't quite caught on to making things simple for the consumer. Found this resource that lists all the different door manufacturers and the models that qualify for the energy tax credit. Pretty helpful to have it all in one place.

Very ironic
Chris,
It's ironic indeed that all U.S. taxpayers are subsidizing the installation of these garage doors, which:
1. Are mostly installed on unheated garages; and
2. Are promoted by deceitful manufacturers that exaggerate the doors' R-values.

It's scandalous -- more evidence, if any is needed, that these tax credits are designed to help manufacturers push products, not to help homeowners save energy.

Garage Door Installation
Very useful information Martin. It helps me how I need to consider U-factor and R-value. As far as I know, the U-factor is typically used with windows as a measurement of how well the product insulates. And coming to R-value, if you find a garage door, for instance, that is thick, the R value might be as high as 6.5. However if you find a lower priced garage door that is made with inexpensive materials, the R value might be something like 4.3. While the numbers may not seem that different, they are. Thanks !

Thanks to Everyone who Posted!
Alaska has an energy rebate program (in addition to the federal program) - up to $10,000 for energy related improvements... some hoops to jump through, but its a great deal. The post on 5/27 gave me a good starting place compare products - plus, it is good to know about the Garaga product. I'll do some cost comparisons locally. Now for the windows, a new boiler/water unit... and some elbow grease to caulk/insulate the gaps!

I can spend $1595 on a R 15.38 door (which as noted above is a misleading metric), that according to my installer has very good air leakage properties from the panel design.

Or I can spend $1050 on a R 8.72 door with poorer leakage problems, but still get the tax credit.

Since my garage is not heated, and between the wife and I the door will be opening and closing several times a day, I think saving the $500 is the smart way to go. There is a bedroom that's beside but above the garage that gets cold in the winter, but I'm thinking if I just open the attic above the garage and put in a good level of insulation along that wall we'll see much better energy savings than from the door we pick.

I just went back to this article you wrote last year and noticed all the comments and questions. There are a few I would like to respond to.

We did test Overhead Doors Model 190 series. The sample tested had an R-value of 7.83. They publish an R-value of 12.76. What’s interesting about this door is that Overhead’s certified statement says that the door has a U-value of .24 or an R-value of 4.17.

We tested a Garaga 138 sample and it came back with an R-value of 7.89. They publish a 12.

If you maintain a 65 degree temperature year round in your garage the actual savings between a door with an R-value of 12 and one with a 4 will be about 7.83 annually.

We recently tested in insulated rolling steel door. The manufacturer published an R-value of 8. The test came back with an R-value of 0.6. If you add air films you would have an R-value of 1.45. Unbelievable.

An honest manufacturer
I sell and install garage doors and we use the manufacturer C.H.I. I believe they are actually honest in their R value publications, their brochures and their specifications sheets use the terminology DASMA TDS #163. I have been hurt as a business several times going up against the manufacturers you've mentioned in this article, because of their inflated values. How do people believe a garage door that's 1 1/2" thick is providing them an R value of 17? I'm sure because it's in writing right on the brochure! I do believe CHI is representing themselves accurately, but it appears to be at a cost. Please see their website at chiohd.com I think you will add them to your list of manufacturers that are trying to play by the real world rules even if it is at a cost.

Thermacore 190 or 490 series / Legacy 696
We are looking for 2 garage doors/openers and have an estimate from Overhead Doors for their Thermacore 190 and 490 series and Overhead Door Legacy 696. Has anyone purchased these doors/openers? Any information would be helpful. Thanks.

Kudos to Haas Doors
I'm building a new garage and found this post very helpful. Thank you Martin. Despite this being a 2 year old post, it seems the industry isn't any more forthcoming with installed door testing now than it was at the time of writing.

One notable exception is Haas Doors. They've taken a step in the right direction by publishing independently tested R-Values for the full door assembly:

Kudos to them. I would guess a lot of manufacturers making good doors are reluctant to publish this information for fear the uninformed consumer would incorrectly assume their doors offer inferior insulation properties. Haas posts it right next to the sectional R-Value, allowing you to see that they compare favorably to the rest of the industry on that (mostly meaningless) measure.

I'm probably going to choose them for my door simply because of their attempt to be honest (It doesn't hurt that they come recommended from a trusted source).

Does anybody else know of a company that posts this information publicly?

Garage doors
The door manufacturers claims could revolutionize the housing industry.
With R-15 to 17 ratings, prefinished and textured finish, it would be cheaper to clad the outside of a house and achieve an R-40 +/- wall rating, using garage door panels.
A challenge for the door people, if they read this.

outswing carriage doors
Do you think that outswing carriage doors would be more efficient, I am building a garage shop that will have very limited garage use but would like to insure that there is some sealing around the doors and it seemed to me that it would be easier to seal outswing solid doors more efficiently?. Thanks

Alaska Garage Doors
Good article. However, if you live in Alaska (Climate Zone 7) and the garage is heated and contains mechanicals (Washer, Drier, and Water Heater), wouldn't the R-18 Clopay that is really an R-7 make sense (with improved sealing, of course)? Or should I just stick with my current wood-paneled door?

Alaska Options
Martin,
Finding your article was.. inspiring!
It has been 3yrs 6 months since you published it - Has anything changed?
Living in AK, building energy efficient, ironically, is NOT that easy. Considering the energy it takes to bring building material to the 49th state.
I am in the planning stage of building a house of small footprint size, and looking at the 'best' solution for a 'can-do-it-all' garage door is a big part of it.
Is it possible that nothing has changed or happened?
One like myself, coming from Europe, would think that garages (and their doors) would get especially in the USA, some attention!
Does anyone have an opinion or experience with HaasDoors, posted above from a member?
What if I would be willing to use my (future) house as a 'test-environment' - Who would be interested and able to process & publish the data?!

My garage is going to be heated, most likely a concrete slab with hydronic radiant floor heating, walls ICF's, in Talkeetna, AK.

Once again, thank you for your article and any help or update on garage doors is greatly appreciated.

Response to Andreas Hermansky
Andreas,
As far as I know, the information in this article still applies, over three years since it was written.

Haas Doors look promising, if only because they are one of the few door manufacturers that doesn't exaggerate (in other words, lie) about the R-value of their doors. However, I have no independent verification of whether Haas Doors perform better than other similar doors.

I was in Talkeetna with my family last summer. We got off the train their for a few minutes -- we were taking the train from Denali National Park to Anchorage. Next time we go to Alaska, we'll have to stay longer.

Best I could find
I got a Garaga door after looking at many. BY FAR the best weather stripping I have ever seen. The interlock of the panels seemed better than any other. It allegedly has a thermal break as well. If nothing else get the Garaga weather strip and install it on your existing door/trim.

Manufacturers Promise Fictitious R-Factors
The garage door industry association, the Door & Access Systems Manufacturing Association (DASMA ) is in the process of performing U factor testing and eliminating R rating on all garage doors. This has been expected for some time as the major manufacturers (Clopay, Overhead Door, Wayne Dalton, CHI, Amarr/Entramatic and others) have been battling over who has the highest R-Factor.

Forty years ago a company, by the name of Mckee Door, did testing on a 10’ x 10’ insulated door that didn’t have weatherseals around the perimeter. They determined that they may as well have a 12 inch diameter hole in the center of the door due to air leakage. Perimeter seals are a major factor in buying an insulated garage door. Regrettably no one in our industry provides anything close to the kind of seals that the window entry door industries provide on their products.

So while consumers and door dealers get hung up on polystyrene/urethane doors with fictitiously high R-Factors, they are doing nothing less than selling the consumer a bill of goods. It’s reminiscent of the same commotion that energy tax credits and pinch-proof doors provided and flooded the industry for a number of years.

A conditioned air space and an insulated garage play a major role in providing a garage with a space that insulates like that of the house. When you drive home in the winter and its 25 degrees, you close the door trapping that cold air in the garage. You might notice the next day when you go outside and the temperature is 40 degrees, when you go back into your garage, you’ll find the temperature is still 25 degrees. So what have you accomplished? Without providing the garage with a conditioned space to balance the temperature, you haven’t achieved anything. The same can be said about the heat. Drive a hot car into a garage when its 100 degrees and go back an hour later and that garage will be over 115 degrees.

A Conditioned space and a door that is tested using a U factor that is based on the doors performance in the opening, not a sample of a door section.

The lesson here is if you want to upgrade your garage door to a steel sandwich door, which is typically stronger and quieter, do so for that reason and not for some fictitious high R-Factor that a manufacturer is promising. It’s obviously unrealistic and incapable of achieving without a conditioned space. Before you go out and spend $4-5000 dollars on making your garage conditioned, you might ask yourself, how often do you intend to really use that space for living type of environment?

Tilt up
For a minimally used garage which, like most garages, will mainly be for storage and workshop, I'm considering alternatives to the roll-top door, partly because I find segmented doors ugly, and partly because I think they are very difficult to make well. Two alternatives are the single piece tilt up and the barn door. The big drawback to the swinging barn door is that it takes up a lot of interior floor area. So what's wring with the good old solid tilt up like my grandmother had? Maybe the edges are difficult to weatherseal.

Response to Ethan T
Ethan,
According to most sources, single-panel garage doors require more space. Moreover, single-panel doors aren't as safe, because they require extension springs which can fail catastrophically. More information at these two sites:

Martin,
CHI specs show a U
Martin,
CHI specs show a U value of 0.058 for the CHI 2216 door (2" polyurethane insulated double steel door with R value 17.19). Can this be correct?
Other competitors that have a similar R value (Clopay 3720 for example listed under sandwich doors on this pdf show U value of 0.16, this one has R value of 18.4).

How is it possible for CHI to have a lower R value (17.19 vs 18.4) than Clopay and yet have a U value of 0.058 which is much better than the 0.16 of Clopay?

Is it possible that Clopay's marketing is that inflated? or is it CHI that is inflating the U value?

Response to KGTG
KGTG,
Q. "CHI specs show a U value of 0.058 for the CHI 2216 door (2" polyurethane insulated double steel door with R value 17.19). Can this be correct?"

A. While it is true that a U-factor of 0.058 is equivalent to an R-value of R-17.19, neither number is credible. The actual thickness of the urethane insulation is 1 7/8 inch, so the implied R-value of the insulation is R-9.17 per inch. This is not credible. To put it another way, it's a lie.

Q. "How is it possible for CHI to have a lower R value (17.19 vs 18.4) than Clopay and yet have a U value of 0.058 which is much better than the 0.16 of Clopay?"

A. Different manufacturers may be purchasing their foam insulation from different insulation manufacturers, so there is no reason to assume that the R-value per inch will be identical from one manufacturer to another. Here's my assessment of Clopay's claims: First, I can't find R-18.4 on the chart that your linked to. I do notice that Clopay has doors with a listed R-value of R-17.2. That would be equivalent to a U-factor of 0.058 (the same as CHI). It's unclear from the table whether the insulation is 2 inches thick, or whether the entire panel is 2 inches thick. If the insulation is 2 inches thick, this implies that the insulation has an R-value of R-8.6 per inch. If the insulation is 1 7/8 inch thick, this implies that the insulation has an R-value of R-9.17 per inch. Neither figure is credible. In other words, it's a lie.

Q. "Is it possible that Clopay's marketing is that inflated?"

A. Yes. Read my article for more examples of this type of lying.

Q. "Is it CHI that is inflating the U value?"

A. A high U-factor is not as desirable as a low U-factor. If CHI wants to exaggerate, they would deflate the U-factor (claim that it is low), not inflate the U-factor (claim that it is high).

Thanks Jon and Martin,
Ah, so
Thanks Jon and Martin,
Ah, so basically, they are just quoting the U values as the inverse of R values and since R values are vastly inflated, the U values would be vastly deflated....Yikes, have they no shame?
I am so frustrated at this, having spent so much time doing the research, I am thinking I should just save my money and go non-insulated, but a heavier gauge steel...

Response to KGTG
KGTG,
The information you linked to is no different from the information provided in my 2010 article.

The FTC has chosen to give the garage door industry a pass on these exaggerations -- presumably because the FTC lacks the resources to pay attention to every variety of R-value exaggeration, and because garage doors don't meet the legal definition of "insulation" under the Federal R-value Rule -- and the garage door industry lacks the guts to get together (as the window industry did) to agree to NFRC-like labels.